MALE ORGANS AND ELEMENTS OF GENERATION. 



881 



tube. Each tube presents a convoluted mass, which can frequently be disentangled under 

 water, particularly if the testicle be macerated for several months in water with a little 

 nitric acid. The entire length of the tube, when thus unravelled, is about thirty inches, 

 and its diameter is from -^ to T f^ of an inch. It begins by from two to seven short, 

 blind extremities and sometimes by anastomosing loops. The caeca! diverticula are found 

 usually in the external half of the tube, and their length is from -fa to % of an inch. The 

 anastomoses are sometimes between the tubes of different lobules, sometimes between 

 tubes in the same lobule, and sometimes between different points in the same tube. As 

 the tubes pass toward the posterior portion of the testicle, they unite into about twenty 

 straight canals, called the vasa recta, about -fa of an inch in diameter, which penetrate 

 the mediastinum testis. In the mediastinum, the tubes form a close net-work, called the 

 rete testis; and, at the upper portion of the posterior border, they pass out of the 

 testicle, by from twelve to fifteen openings, and are here called the vasa efferentia. 



Having passed out of the testicle, the 

 vasa efferentia form a series of small, con- 

 ical masses, which together constitute the 

 globus major, or head of the epididymis. 

 Each of these tubes, when unravelled, is 

 from six to eight inches long, gradually 

 increasing in diameter, until they all unite 

 into a single, convoluted tube, which forms 

 the body and the globus minor of the epi- 

 didymis. This single tube of the epididy- 

 mis, when unravelled, is about twenty feet 

 in length. 



The walls of the seminiferous tubes in 

 the testicle itself are composed of connec- 

 tive tissue, a basement-membrane, and a 

 lining of granular, nucleated cells. In the 

 rete testis, it is uncertain whether the tubes 

 have a special fibrous coat or are simple 

 channels in the fibrous structure. They 

 are here lined with pavement-epithelium. 

 In the vasa efferentia and the epididymis, 

 we have a fibrous membrane, with longi- 

 tudinal and circular fibres of involuntary 

 muscular tissue and a lining of ciliated 

 epithelium. The movement of the cilia is 

 toward the vas deferens. In the lower 

 portion of the epididymis, the cilia are ab- 

 sent. The tubular structures of the testicle, 

 the epididymis, and the commencement of 

 the vas deferens are shown in Fig. 282. 



At the lower portion of the epididymis, communicating with the canal, there is 

 usually found a small mass, formed of a convoluted tube of variable length, called the 

 vas aberrans of Haller. (i, Fig. 282.) This is sometimes wanting, and its function, 

 which cannot be very important, is unknown. 



Vas Deferens. The excretory duct of the testicle extends from the epididymis to the 

 prostatic portion of the urethra and is a continuation of the single tube which forms the 

 body and globus minor of the epididymis. It is somewhat tortuous near its origin and 

 becomes larger at the base of the bladder, just before it is joined by the duct of the semi- 

 nal vesicle. Near its point of junction with this duct, it becomes narrower. Its entire 

 length is nearly two feet. 



56 



FIG. 282. Testicle and epididymis of the human sub- 

 ject. (Arnold.) 



a, testicle ; 6, &, ?>, &. lobules of the testicle ; c, c, vasa rec- 

 ta; d, d, rete testis ; e, e, vasa efferentia ; f,f,f, cones 

 of the globus major of the epididymis; g, g, epi- 

 didymis ; h, ^, vas deferens ; i, vas aberrans ; m, m, 

 branches of the spermatic artery to the testicle and 

 epididymis ; n, ., w, ramification of the artery upon 

 the testicle : o, deferential artery ; p, anastomosis of 

 the deferential with the spermatic artery. 



